Related Stories

A super-thin glue that gets stickier when you heat it has been developed by US scientists.

They say the nanoglue, made from self-assembling nanoscale chains of molecules, could be used to 'hook' together two surfaces that don't normally stick well.

"Our work shows the possibility of having organic-based nanolayers that are about a 1000 times thinner than the thinnest organic-based glues," says Professor Ganapathiraman Ramanath, whose work appears in the journal Nature.

"It is really mind-boggling to think about a single layer of molecules improving the adhesion of something," says Ramanath, a materials science researcher from the Rensselaer Polytechnic Institute.

Glues have been made with layers of molecules thin as one-millionth of a metre, but never before with a thickness of one nanometre, one-billionth of a metre.

"This is a single layer of molecules that are organised like soldiers," Ramanath says. The glue chain lines up in very orderly fashion all on its own.

"Nature does most of it for you," Ramanath says. "You just have to put the right thing on the top and the right thing on the bottom and it will work."

The glue has a backbone of carbon molecules. On one end of the chain is silica and oxygen and on the other is sulfur. These different end-molecules act as hooks that bind to other surfaces.

Ramanath topped off the chain with a thin layer of copper that acts as a protective coating to help keep the molecules intact.

When heated to 400°C or higher, the copper and silica form a strong chemical bond, which increases the glue's stickiness by five to seven times.

"When you heat it, it becomes a better glue," he says. "That was something we hadn't bargained for."

He says the glue could be used as an inexpensive way to connect any two materials that do not bond well.

And the cost (US$35 per 100 grams) would make it a fairly cheap commercial option, he says.

Ramanath and his team are seeking a patent for the material, which he thinks could be used in the development of chips used in any type of microelectronic device.